<!-- <style>
    h1 {
        color: red;
    }

    h2:invalid-pseudo {
        color: red;
    }

    h3 {
        color: red;
    }
</style> -->

<style>
    h1,
    h2:invalid-pseudo,
    h3 {
        color: red;
    }
</style>
<h1>h1</h1>
<h2>h2</h2>
<h3>h3</h3>